The present invention relates to hydraulic vibration-damping supports.
More particularly, the invention relates to a hydraulic vibration-damping support serving to interconnect two rigid elements for damping purposes, the support comprising at least:
first and second rigid strength members serving to be fixed to respective ones of the two rigid elements to be interconnected;
an elastomer body interconnecting the first and second strength members;
a working chamber filled with liquid, and defined in part by the elastomer body;
at least one easily-deformable compensation chamber; and
a decoupling flap which comprises a flexible membrane that is mounted to move with clearance between first and second rigid gratings that communicate respectively with the working chamber and with the compensation chamber, the first and second gratings being carried respectively by first and second rigid support pieces fixed to the second strength member.
Document FR-A-2 714 947 describes an example of such a vibration-damping support which is quite satisfactory.
A particular object of the present invention is to improve vibration-damping supports of this type further so as to reduce any banging noise that might appear due to the flexible member of the decoupling flap moving between the two gratings of said flap, in particular when the vibration-damping support serves to mount the engine-and-gearbox unit of a vehicle on the body of the vehicle.
To this end, in the invention, in a vibration-damping support of the type in question, the first and second gratings are connected by elastic links to respective ones of the first and second support pieces (the elastic links in question may optionally be constituted by two zones on the same elastic piece).
By means of these provisions, the movements of the membrane of the decoupling flap against the gratings of said flap are damped due to the flexibility of said elastic links, thereby making it possible to limit or even eliminate the banging noise due to the decoupling flap.
In preferred embodiments of the invention, it is optionally possible, in addition, to use any of the following provisions:
said elastic links are elastomer links;
said elastic links have stiffness lying in the range 100 newtons per millimeter (N/mm) to 200 N/mm along an axis that is perpendicular to the first and second gratings;
the first and second support pieces and the first and second gratings together form a partition which separates the working chamber from the compensation chamber;
the first and second support pieces are annular and surround respective ones of the first and second gratings, said first and second gratings being connected to respective ones of the first and second support pieces via first and second elastomer bands which constitute said elastic links;
the first and second support pieces define a constricted passage which puts the working chamber continuously into communication with the compensation chamber;
the first and second elastomer bands are molded over and bonded to respective ones of the first and second gratings and respective ones of the first and second support pieces;
the first and second gratings and the first and second support pieces are pieces of cut-out sheet metal that are part of a partition separating the working chamber from the compensation chamber, the first and second support pieces defining at least in part a constricted passage which puts the working chamber continuously into communication with the compensation chamber;
each of the first and second gratings has a crenelated outer periphery while each of the first and second support pieces has a crenelated inner periphery, the crenelated inner periphery of each support piece being substantially complementary to the crenelated outer periphery of one of the gratings; and
the outer periphery of each of the first and second gratings forms crenellations that project radially outwards, and the inner periphery of each of the first and second support pieces forms crenellations that project radially inwards, the crenellations of the first and second gratings being disposed substantially in mutual register with the crenellations of the first and second support pieces.